Balancing a burgeoning hobby alongside long work hours can be demanding. Bill Knight explains how stepping back from law helped him to develop his passion in photography

If you bought your first camera in 1956 it is likely to have been a Kodak. Mine was a Kodak Brownie Cresta, a chunky plastic box which took square pictures in, of course, black and white. It had two controls – the shutter button and a knob for winding on the film. If you did not wind the film immediately after each shot, you were in trouble: when you next used the camera you couldn't remember whether you had wound on or not, so you risked the meaningless jumble of a double exposure if you didn't wind on, or a blank if you did.

Greylag geese landing at Wicken Fen The overcast sky helps with the colours. This was taken with my 400mm F 2.8 Nikkor – the football lens – the front element of which is so big that I could not get it though the embrasure in the hide. Although the geese were a long way away, luckily they were right in front. The RSPB calls these birds in England 'semi-tame and uninspiring' – rather rude I think

PG Wodehouse wrote that a man becomes a golfer when he first hits a drive straight and true down the fairway. In a similar way, you get hooked on photography when you take your first decent picture. Mine was a portrait of my brother in the living room, taken when I was 12 with the Brownie, and set up with a bright photoflood bulb in an Anglepoise lamp. To me it looked better than real life.

My next camera took 35mm film. It had a fixed lens and you had to set the shutter speed, aperture and focus. I bought a range finder and a primitive light meter and learned to develop and print in black and white. Every photograph is a slice of light, and by mixing and matching the aperture and the shutter speed, you can change the way the camera sees the image while keeping the total amount of light constant. Learning this is good if you want to take decent pictures. With a modern digital point and shoot, you really have no idea what is going on.

Alexandra Marks, the president of the City of London Law Society This is a studio portrait. It took some time to get the wary look out of Alexandra's eyes but we did it in the end and she looks great

In my summer holidays before university, I was a beach photographer on the prom at Margate, and that taught me a thing or two as well. Fill the frame but don't cut the feet off; get their faces in the light but not too harsh; and above all, make them smile and relax. "I say, madam, you're looking very happy this morning," I used to comment.

The law and photography don't go together, so there was a blank in my photographic career after entering articles in 1967. For a long time my films were like most other people's – they had a Christmas tree at each end and a baby in the middle. Moving to Hong Kong in 1979 to open the Simmons & Simmons office made a difference. If you live and travel in Asia, you really want to take pictures. I bought my first single lens reflex camera – a Pentax – and, importantly, a 200mm lens. Once you start to change lenses you start to think about composition and light like a photographer.

Shaun Dooley in Stovepipe, a HighTide production in collaboration with the National Theatre This play is promenade theatre – the audience walks through the sets – and it takes place under a shopping centre in Shepherd's Bush. This meant I, as the photographer, could get really close

Back in the UK, I switched to Nikon. Every serious photographer gravitates to Nikon or Canon eventually because they are cameras made with great precision by very obsessive people and have an enormous range of lenses. I had a darkroom in the basement, but work was getting in the way and it wasn't until I retired from Simmons & Simmons in 2001 that I could really get on with it. Luckily the industry obliged, with a timely switch to high-quality digital cameras and computer processing. Anyone who has struggled with film knows the delight of being able to process in colour at home. Any photographer today who wants to control his images has to spend time mastering Adobe Photoshop and losing himself in the intricacies and intuitive interface of what must be the best computer programme available off-the-shelf anywhere. With Photoshop, you can do anything to an image, from optimising the colours to full-scale changes. My son calls it 'mad fiddling'.